Allergy Drugs: Prescription and OTC

Jim Morelli, MS, RPh

Jim Morelli holds a B.S. from the Massachusetts College of Pharmacy and Allied Health in Boston and an M.S. in civil engineering from Tufts University. He is registered as a pharmacist in the state of Georgia.

Omudhome Ogbru, PharmD

Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

What are allergies?

Allergies occur when the body's immune system responds to a substance it considers an "invader." Substances that provoke the immune system into an allergic response are known as allergens. There is no such thing as a universal allergen. What might trigger a life-threatening allergic response in one person might cause absolutely no harm in another.

The physiological mechanism of allergic reactions is the same, however, in everyone. Allergens enter the body -- either through ingestion, inhalation or contact with the skin or mucous membranes. This causes white blood cells to release an antibody which then binds to what are known as mast cells. The mast cells rupture – and in the process, release biochemical substances including histamine.

Allergy medication list

How They Work:

Antihistamines used to treat allergy symptoms fall into two broad categories: sedating and non-sedating. The first category includes the older antihistamines. These allergy drugs relieve allergy symptoms but cause drowsiness and other side effects, including dry mouth. Newer antihistamines are said to be non-sedating, although some users may experience drowsiness even from these.

All antihistamines work in the same way: by competing with histamine to prevent or reduce the characteristic signs and symptoms of an allergic reaction: swelling, tearing, itching, and increase in bronchial and other secretions.

Corticosteroids: These come as nasal sprays, topical creams and ointments, tablets, injectables and eye preparations. Corticosteroids work by reducing inflammation.

Mast cell stabilizers: These can help prevent allergic reactions from happening when taken regularly. During an allergic reaction, mast cells release histamine and other substances. Mast cell stabilizers, such as cromolyn sodium, keep these cells intact.

Leukotriene inhibitors: Other substances released during an allergic reaction are leukotrienes, which can aggravate allergic conditions and asthma. Some drugs target leukotriene receptors to reduce allergic symptoms.

Decongestants: These relieve a stuffy nose by constricting blood vessels, which limits the amount of secretions coming from the inner lining of the nose. They are available as nasal sprays, pills, and liquids. They don't relieve other allergy symptoms such as itching and sneezing.

Immunomodulators: These are topical medications used to treat skin allergies. They are often used if other agents are ineffective or intolerable.

Autoinjectable epinephrine: This is used to treat a life-threatening allergic reaction known as anaphylaxis, which may be caused by severe allergic response to foods, drugs, or insect stings.

Allergy medication side effects

Older antihistamines are associated with drowsiness, dizziness, constipation, upset stomach, blurry vision, a dry mouth/nose and throat, and difficulty urinating. The newer antihistamines are usually well tolerated but can cause drowsiness, dry mouth, and stomach problems.

Topical immunomodulators may interact with:

What is the best allergy medication?

The best choice of allergy medication is one which relieves symptoms without interfering with everyday tasks. Many allergy sufferers are finding that the newer, non-sedating antihistamines meet both these important parameters. It's also important to find an allergy medication that can safely be used for the long term, since for many, allergies last an entire season – if not the entire year. And finally, allergy medications should minimally react with other medications.

What can you do if your allergy medication is not working?

Allergy shots, also known as immunotherapy, may eliminate or lessen allergy symptoms if medications are ineffective or intolerable. Immunotherapy works by reducing sensitivity to allergens. Each shot contains a small, but increasing, amount of allergen. This challenges the body to build up tolerance over time. The drawbacks to immunotherapy include use of shots, cost and the fact it may take many months to complete.

Allergy medication for toddlers

Allergy medications are not recommended for use in children under the age of two years without out the advice of a physician. In this group, mild symptoms can be managed using non-drug methods such as saline spray for a stuffy or dry nose and/or a vaporizer/humidifier for congestion. If the allergy is in the form of a rash, emollient creams may offer some relief. For more severe allergy symptoms – widespread rash, wheezing, red, watery eyes – parents should consult a pediatrician.

Allergy medication for children

Many over-the-counter antihistamines are safe for use in children beginning at the age of two – and several come in a liquid dosage form (loratadine, diphenhydramine) which makes them easy to administer. Parents should pay careful attention to dosing.